Pipelines, which extend for many miles, are constructed by welding together sections of pipe. The welding together of the pipe ends is a major aspect in the cost and time required for the construction of the pipeline. In order for welding equipment to be applied to weld the pipe sections, the ends of the pipes must be accurately aligned with each other and held rigidly in position where the welding takes place. One way of holding the pipe sections in position is by use of an internal line-up clamp. Internal line-up clamps are shown in U.S. Pat. No. 5,356,067 and U.S. Pat. No. 5,535,938. A self-powered internal line-up clamp and internal welding apparatus is described in U.S. Pat. No. 5,059,765. These line-up clamps require the use of a reach rod or tether line for moving and positioning the line-up clamp at the abutting ends of the pipe sections and this rod or line must be passed through each new pipe section.
A bending mandrel is a device that is positioned within a section of pipe so that the pipe section can be subjected to outside forces and bent to a desired configuration. The mandrel prevents the pipe wall from collapsing during the bending process and producing an uneven or distorted pipeline wall. Such a pipeline mandrel that includes an apparatus for remote control positioning is shown in U.S. Pat. No. 6,092,406. A positioning apparatus for use with pipeline equipment is shown in U.S. Pat. No. 5,651,638. It has heretofore been known to use a diesel engine mounted to a pipe mandrel for providing motive and other operational power to the mandrel.
Due to the substantial time and effort required to move and then accurately position an internal line-up clamp, there exists a need for a line-up clamp unit that is self-powered so that it can be moved through pipeline segments and then be positioned accurately without the need to repeatedly position a rod or tether line that is used for controlling and moving the clamp unit.